The dimensions of the opening (e.g., passageway) through the sidewall of a vessel (e.g., a gunwale) govern the accessibility and therefore the easy in which an individual and cargo can traverse on and off a marine vessel. The passageway is limited by the height of the opening and the width of the opening. The height is limited by the distance between decks on multi decked vessels. The width is limited by the horizontal distance across the opening. The opening is commonly governed by the respective size of a doorway.
The ship building industry is familiar with many types of sliding and swinging door assemblies and other means for obtaining access to the vessel's deck and interior spaces. A few examples of these door and boarding devices include, companionway doors, and various folding ladders and stairs as well as retractable gangways. Typically, swinging boat doors are limited to standardly affixed and hinged designs for single doors and/or multipart doors that swing back and forth to allow access to the vessel.
Hinged boat doors require a clearance for opening. This limitation can introduce complications in the design requirements as the doors are typically pivotally cantilevered on one side by one or more hinges. This configuration can introduce several challenges for the marine engineer to consider. For example, standard hinged boat door assemblies can create undesired strains on supporting structures as well as necessitate accommodation of the hinge and closures mechanisms, and finally, hinged doors require sufficient clearances to open and close. The necessary design allowances can intrude upon the vessel's available interior deck space as well as reduce the opening dimensions. The design aesthetics of the vessel that are very important in high end and luxury marine vessels (e.g., pleasure boats, yachts, cruise ships, and the like) markets for can also be adversely impacted by these design accommodations.
Aside from hinged doors, some other vessel designs include sliding doors between the exterior deck of the vessel and the cabin interior. A sliding door is often preferred over a hinged types of boat doors because of space requirements and the negative implications of a hinged door suddenly swinging in either direction due to rolling seas. Indeed, a swinging door could severely injure one person while he or she is trying to enter or exit through such door when the rolling of the vessel due to rough seas suddenly swings the door toward the person.
Pocket sliding doors are sliding doors in which at least a portion of the door is withdrawn into an enclosure. Such doors are well known in residential housing and offices, and have also been used in vessels where swinging doors are undesirable. Pocket doors are usually straight, however, it is known to use curved pocket doors in corner cabinets, furniture, and the like.
Pocket doors could potentially be used in a boat transom or other external positions on a boat, but they would be limited. For instance, known pocket door designs are usually hung from above and/or supported from below and therefore require one or more stabilizing tracks, rollers, and guide systems, that run the length of the path of the door. Nevertheless, one or more tracks crossing the opening of the boat's transom would be undesirable for a number of reasons, including but not limited to, the tracks would diminish from the design aesthetic, they would tend to fill with water and other debris, and it could even comprise a danger during ingress and egress. These problems would be exacerbated for boats having a door in a curved, angled, or complex cross sectioned transom and/or gunwale. Such doors would have to be similarly shaped as well, which would be especially hard to implement without existing track technologies across the opening.
There are number of conventional boat boarding door systems. However, none provide a pivoting and sliding boat door boarding system that can be opened and closed without altering the original height, shape, and design aesthetic of the vessel's exterior (e.g., gunwale) while providing easy entry to the vessel's deck and interior spaces.